Muffler



Oct. 4, 1932. 1.. HAAS 1,881,051

/ MUFFLER Filed Jan. 16, 1929 2 Sheets-Sheet 1 //V VF/V TOR.

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UNITED STATES PATENT OFFICE LUCIEN L. HAAS, 0F BUFFALO, NEW YORK, ASSIGNOR TO BUFFALO PRESSED STEEL 00., OF BUFFALO, NEW YORK MUFFLER Application filed January 16, 1929. Serial No. 332,948.

This invention relates to mufliers or silencers for use in connection with elimination of noise caused by the flow of gases, for example, from the exhaust manifold from internal combustion engines.

The objects of this invention are to produoe a mufller of this kind having a series of nested shells forming a novel arrangement of chambers into which the exhaust gases flow for the purpose of reducing the pressure and eliminating noise caused thereby; also to provide a muffler of this kind with a novel arrangement of passages for conduct- 4 ing gas'from one chamber to several other chambers to improve the mufiiing efiect of the device; also to improve the construction of mufliers of this kind in other respects hereinafter specified.

In the accompanying drawings Fig. 1 is a longitudinal central sectional elevation of approximately half of a mufller, a portion of one of the interior shells being I completely shown.

Fig. 2 is a central longitudinal sectional view of the other half of the mufller.

Figs. 3 and 4 are transverse sectional views thereof on lines 33 and 4-4 of Figs. 1 and 2 respectively.

Figs. 5 and 6 are central sectional elevations similar to Figs. 1 and 2, showing a muffler of slightly modified construction.

Fig.7 is a transverse sectional view thereof on line of Fig. 6.

The muffler includes an outer shell 10, the

" opposite ends of which are partlyclosed by means of heads'll and 12.

The mufiler is also provided with an in ner shell 14 which in the particular construction shown in Figs. 1-4 extends through the muffler from end to end and is secured at its opposite ends to the heads 11 and 12. For this purpose, these heads may be provided with annular shoulders or offset portions 15 and 16 which receive the ends of the inner shell 14 and if desired, the heads may also be provided with tubular extensions 17 and 18, the extension 17 communicating with the exhaust pipe of the engine to receive products of combustion discharged from the engine, and the extension 18 forming the discharge of the muiiier.

The inner shell 14 is divided by a transverse wall or partition 19 into an inlet and a discharge chamber or portion.

The annular space formed between the outer and inner shells 10 and 14 is preferably divided into two compartments by iieans of a transverse partition 20. This transverse partition in the particular construction shown is provided with inner and outer cylindrical flanges which are secured to the inner and outer shells of the muifier in the usual manner.

Either or both of the two compartments at opposite sides of this partition may be divided. into a plurality of flow passages or mufiling chambers. In the particular construction illustrated, only one of these compartments is so divided, namely, the one adjacent to the intake of the muflier, this compartment being divided into two spaces by a substantially trusto-conical shell 22, one end of which in the construction shown also engages the shouldered portion 14 of the head 11 and the other end of which is secured to a shoulder 23 of the transverse partition 20. This frusto-conical shell 22 is preferably so formed that the larger end thereof is elongated or substantially elliptical in cross section, while the other or smaller end thereof is of circular cross section. This formation of the shell 22 is effected by forming the shoulder 23 on the transverse partition 20 of elliptical shape as is clearly shown in Fig. 4, and then fitt ng the larger end of this shell over the shoulder and securing the same thereto.

As a result of this construction the two chambers into which the compartment is divided by the wall 29. are of irregular shape having some portions of greater cross sectional area than other portions, so that a very effective mufiiing is produced by causing the gases to flow in these chambers through the spaces of varying cross sectional areas. Other forms of shells or partitions may be provided in the muliler, if desired.

The inlet portion of the inner shell 14 of the muffler is provided with an opening or series of apertures 25 into which the major portions of the gases entering the shell pass. From these apertures the gases pass into that portion of the surrounding chamber which is of reduced cross sectional area as shown in Fig. 4. The gases expand in this chamber by flowing radially toward the port-ion thereof of larger cross sectional area and longitudinally toward the discharge opening in the intermediate shell 22 which is in the form of a series of apertures 26. These apertures 26 are so arranged with reference to the apertures 25 that the gases in the chamber etween the inner shell '14 and the shell. 22 must pass through approximately a quarter of a turn to reach the discharge opening 26. The gases after passing through the discharge opening 26 are in. the outer chamber and flow lengthwise in this chamber and through apertures 27 formed in the transverse partition or wall into the compartment between the inner shell 14 and the outer shell 10 and adjacent to the discharge end of the mufller. From this compartment the gases pass into the discharge chamber of the inner shell through a series of openings 28 arranged at opposite sides of the inner shell, and the ses are consequently discharged from the mufiler through the discharge passage 18.

In order to assist in the muflling of the gases it has been found very effective to discharge some of the gases through an opening or apertures near the intake end of the inner shell 14, and for this purpose open s 29 are provided, these openings being of such size as to permit only a relatively small part of the gases to flow through the same.

However, the gases which flow through the openings 29 pass toward the apertures 26 in the shell 22 in a direction opposite to the direction of travel of the gases which have been passed through the main. discharge openings of the receiving portion of the inner shell, and this flow in opposite directions assists in the mufliing of the noise.

A further improvement in the s lencing of the noise of the gases, and a simultaneous reduction in the back pressure produced by the mufiler results in the providing of additional openings or apertures 31 in the intake portion of the inner shell and beyond the transverse partition 20. These apertures are also of fewer number or of smaller size than the apertures 25'so that only a small portion of the gases entering the intalre part of the inner shell passes through the openings 31.

- These gases, however, pass directly into the final expansion compartment of the mufiier and therefore do not have to pass through the several chambers of the preliminary expansion chamber and thus to a certain extent reduce the back pressure caused by the muffler. By discharging the gases radially into contact with the longitudinally flowing gases passing out of the apertures 27 in the transverse partition 20, a muflling of the noise results.

The mufiier shown in Figs. 5 to 7 is similar in construction to the one shown in Figs. 1 to 4 except that the inner shell of the muflier in this case does not extend throughout the length of the muffler. In this construction the outer shell of the muffler may be made somewhat shorter and the inner shell 34 terminates at a transversely extending partition or head 35 which corresponds substantially to the transverse head 20 shown in Figs. 1 to 4 but which has a central imperforate head 36 around which the inner shell 34 fits and which closes the end of the inner shell.

The intermediate shell 22 is the same as shown in Figs. 1 to 4 and consequently the arrangement of the shells and the chambers formed thereby in the compartment extending from the partition 35 to the head 11 at the receiving end of the mufiler are the same as in the other construction. The space between the partition 35 and the head 1.2 forms a compartment 38 into which the gases enter through the discharge openings 39 in the intermediate head or partition 35, and after expanding in the chamber 38, the gases pass out through the extension 18 of the head 12. This muflier is of somewhat simpler form than the one shown in Figs. 1 to 4, and has been found very satisfactory for use in connection with somewhat smaller engines.

The mufiler in both of the forms described is of inexpensive construction and consists of relatively few parts, and it will be noted that the structure results in the gases flowing from the inlet to the discharge of the mufiler through chambers which increase successively in size, which has been found to produce an improved mufiling effect, and with less back pressure than is commonly produced in mufflers having an equal silencing effect. 2

I claim A 1. In a mufller, the combination of an outer shell, a transverse partition dividing said shell into two compartments, said partition having passages therethrough through which gases may flow from one compartment to the other, an inner shell extending through said mufiler and said partition, atransverse dividing wall in said inner shell and arranged out of alignment with said partition, the portion of said inner shell at one side of said dividing wall receiving gases and the other portion of said inner shell discharging gases from the muffler, said first mentioned portion of said inner shell being provided with aperof alignment with 7 tion of said inner shell communicating with the compartments at both sides of said partition and said other portion of theinner shell being provided with apertures communicating with only one of shell, a transverse partition dividing said shellxinto two compartments, said partition having passages therethrough through which gases may flow from one compartment to the other, an inner shell extending through said muffler and said partition, a transverse dividing wall in sa inner shell and arranged out of alignment with said partition, the portion of said inner shell at one side of said dividing wall. receiving gases and the other pordischarging gases from the mufiier, the receiving portion of said inner shell being provided with opein. communicating with both compartments opposite sides of said partition, and said other portion having apertures communicating with only one of said compartments.

3. In a muffler, the combination of an ou shell, a transverse partition divid ng shell into two compartments, said pa having passages therethrough through which gases may flow from one compartment to the other, an inner shell extending through said muffler and said partition, a transverse di i ing wall in said inner shell and arranged out said partition, portion of said inner shell at one si of said dividing wall receiving gases the other portion of said inner shell discharging gases from the muflier, the gas receiving portion of said inner shell being provided with apertures through which the major portion of the gases pass into the compartment adjacent to the inlet end of said muffler and a restricted opening through which a lesser portion of the incoming gases may pass to the other compartment, the discharge portion of said inner shell being provided with openings sly).

throu h which ases ma ass from said last mentioned compartment.

4. In a mufller, the combination of an outer shell, a transverse partition dividing said 7 shell into two compartments and having passages therethrough through which gases may flow, an intermediate shell arranged in one of said compartments for dividing the same into muiiling chambers, said intermediate shell having passages through which the gases may flow from one of said chambers to another, an inner shell in said mufiier, a transverse wall in said inner shell dividing the same into gas receiving and gas discharging portions, a main discharge opening in said gas receiving portion through which gas may be discharged into said mufliing c iambers at one side of said transverse partition and a lesser opening through which a relatively smaller portion of said gases may be discharged into the compartment at the other side of said partition, and apertures in the discharge portion of said inner shell communicat-ing with said last mentioned compartment through which gases may pass from said last mentioned compartment to the discharge portion of said inner shell.

5. In a mufiier, the combination of inner and outer shells, heads connecting the end portions of said shells, a transverse partition intermediate of said heads and extending from said inner shell to said outer shell and dividing the space between said inner and outer shells into two compartments, a trans verse wall in said inner shell dividing the same into gas receiving and gas discharging portions, an intermediate shell arranged in the compartment adjacent to the gas receiving end of the muff r, passages through said inner and inter-med shells said pa tion to cause from the receming portion of said inner shell to flow first through chambers formed in one of said compartments by said intermediate shell and then to the other compar naent through said transverse partition and then into the discharge portion of said inner shell, and an opening in said re- -eiving portion of said inner shell for di charging a lesser portion of gas entering the receiving portion of said inner shell directly into said other compartment in a direction at an angle to the flow of gas into said other compartment through said apertures in said transi' erse partition.

6. In a muffler, the combination of an outer shell, heads connected to said outer shell adjacent to the ends th reof, one of said heads being provided with an inlet opening for admitting gases to the r uiiier and the other head having a discharge opening for the gases, a. transverse partition arranged between said inner and outer heads and dividing said muiiier into two compartments, an inner shell communicating at one end with the inlet opening in one of said shells, an intermediate shell arranged in the compartment at the inlet end of the muffler and extending from the head at the inlet end thereof to said transverse partition and being of smaller diameter at the portion thereof acent to the inlet head than at the port-ion thereof adjacentto said partition, said inner shell having discharge openings for gases arranged adj acent to said partition, said intermediate shell having discharge openings arranged at a distance from said partition, and trans verse partition having discharge openings adjacent to said outer shell through which gases may pass from the compa adjacentto the inlet end of the mufiier to the other compartment.

7. In a mother, the combination of an outer shell, headsconnected to said outer shell adjacent to the ends thereof, one of said heads end thereof, and heads to being provided with an inlet opening for admitting gases to the muiiier and the other head having a discharge opening for the gases, a transverse partition arranged between said inner and outer heads and dividing said mufller into two compartments, an inner shell communicating at one end with the inlet opening in one of said shells, an intermediate shell arranged in the compartment at the inlet end of the muffler and extending from the head at the inlet end thereof to said transverse partition and being of smaller diameter at the portion thereof adjacent to the inlet head than at the portion thereof adjacent to said partition, said inner shell having a relatively large number of discharge openings adjacent to said transverse partition and a smaller number of discharge openings adjacent to said inlet head and said intermediate shell having discharge openings arranged intermediate of the discharge openings in said inner shell, whereby gases will flow in opposite directions in the space between the inner and intermediate shells, said partition having discharge openings adj acent to the outer edges thereof for permitting gases to flow from the compartment adjacent to the inlet end of the muffler to the other compartment.

8. A muffler having inner and outer sub stantially cylindrical shells and an intermedi ate substantially conical shell, heads to which the ends of said shells are secured, said shells and heads forming chambers in which the gases flow and which chambers have converging walls, and apertures in said inner and intermediate shells for causing the gases to flow into the larger ends of said chambers.

9. A muffler having inner and outer substanti ally cylindrical shells and an intermediate tapering shell, heads to which the ends of said shells are secured, said heads having shouldered portions to which said shells are secured, said tapering shell being secured at one end to the same shouldered portion as one of said other shells, said shells and heads forming converging chambers in which the gases flow, and said inner and intermediate shells having apertures through which gases flow into the larger ends of said chambers.

' 10. In a muffler, the combination of an inner and an outer substantially cylindrical shell, an intermediate substantially conical shell which is substantially elliptical at one which said shells are secured, said shells having passages for conducting gases successively into the ends of greatest cross sectional area of the several chambers formed by said shells and heads.

11. In a muffler, the combination of an in ner and an outer substantially cylindrical shell, an intermediate substantially conical shell which is substantially elliptical at the larger end thereof, heads to which the ends of the shells are secured, said shells and heads forming chambers with converging walls through which gases flow, said inner and intermediate shells having apertures for'discharging gases into larger portions of said chambers, said inner shell having its apertures arranged to discharge the gases adjacent to the minor axis of the elliptical curvature of the larger end of said intermediate shell. i

12. In a mufiler, the combination of alternately arranged shells of substantially circular and elliptic cross section, at least one of said shells tapering to form chambers between shells varying in cross sectional area from one end of each chamber to the other end thereof, heads to which the ends of the shells are secured to cooperate with said shells to form said chambers, and apertures in the shells to conduct gases into the chambers between adjacent shells into the end of greater cross sectional area of each chamber.

LUCIEN L. HAAS.

Ill 

